High-Sensitivity Temperature Sensor Based on Polarization Maintaining Fiber Sagnac Loop

Laipeng Shao,Yiping Wang,Tianyin Wu,Jing Du,Hanglin Lu,Junhui Hu

doi:10.1007/s13320-018-0517-6

Laipeng Shao, Yiping Wang + Show 4 more

Open Access

https://doi.org/10.1007/s13320-018-0517-6

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Journal: Photonic Sensors	Publication Date: Oct 25, 2018
Citations: 29	License type: open-access

Affiliation: Shenzhen University, Guangxi Normal University

Abstract

A high-sensitivity all-fiber temperature sensor based on a Sagnac interferometer is demonstrated by splicing a section of polarization maintaining fiber (PMF) between two sections of standard single mode fibers (SMFs). In this sensor, the SMF-PMF-SMF structure in the Sagnac loop is bent into a circle to enhance the sensitivity. The length and curvature of the PMF in the loop are investigated and can be optimized to further increase the temperature sensitivity of the sensor. Results show that the radius of the circle has an important effect upon temperature sensitivity due to the bend-induced birefringence variation of the PMF. The SMF-PMF-SMF structure bent into a circle with a radius of 30 mm exhibits a high-sensitivity temperature of 1.73 nm/°C. The sensor is provided with the advantages of easy fabrication, low-insertion loss, and high sensitivity, which may find potential applications in the field of high precision temperature measurement.

Highlights

Interferometric fiber optic sensors combined with mode interference structure and Sagnac loop have shown the advantages of high sensitivity, stable and simple structure, and compatibility and low prices [1,2,3]
In order to optimize the length of polarization maintaining fiber (PMF), we first investigate the temperature sensitivity dependence of the PMF length before the single mode fibers (SMFs)-PMF-SMF structure is bent into a circle
The SMF-PMF-SMF structurebased Sagnac loop is placed in an incubator (WD2005) with a resolution of 0.1 °C

Summary

Introduction

Interferometric fiber optic sensors combined with mode interference structure and Sagnac loop have shown the advantages of high sensitivity, stable and simple structure, and compatibility and low prices [1,2,3]. This type of interferometer can be fabricated by splicing a segment of multimode fiber (MMF) between two standard single mode fibers (SMFs), i.e. the SMF-MMF-SMF structure. Liu et al [9] proposed a high-sensitivity temperature and strain sensor based on mode interference in graded-index multimode fibers, and a temperature sensitivity of 58.5 pm/°C

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Results

Conclusion